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S Almeida

Publications and source records attributed to S Almeida.

At least 19 recordsLinked to original sources
PubMed2006

Estrogen receptor 1 gene polymorphisms and coronary artery disease in the Brazilian population.

We examined the association of three established single nucleotide polymorphisms, IVS1-397T>C, IVS1-351A>G, and +261G>C, in the ESR1 gene with the prevalence and severity of coronary atherosclerosis in a southern Brazilian population of European ancestry. Three hundred and forty-one subjects (127 women and 214 men) with coronary artery disease (CAD) were classified as having significant disease (CAD+ patient group) when they showed 60% or more luminal stenosis in at least one coronary artery or major branch segment at angiography; patients with 10% or less luminal stenosis were considered to have minimal CAD (CAD- patient group). The control sample consisted of 142 subjects (79 women and 63 men) without significant disease, in whom coronary angiography to rule out the presence of asymptomatic CAD was not performed. The polymorphisms were investigated by polymerase chain reaction followed by restriction analyses. In the male sample, the +261G>C*C allele was more frequent in CAD+ than CAD- subjects (8 versus 1%, P = 0.024). Homozygosity for the C allele of the IVS1-397T>C polymorphism was also significantly associated with increased CAD severity (OR: 2.99; 95% CI = 1.35-6.63; P = 0.007). In agreement with previous findings, these results suggest that the IVS1-397T>C*C allele was associated with CAD severity independent of gender, whereas the association of the +261G>C variant with CAD was observed in males only. The relation between ESR1 variation and CAD may influence clinical decisions such as the use of hormone therapy, and additionally will be helpful to identify the genetic susceptibility determinants of cardiovascular disease development.

Brazil↗
PubMed2006

Isolation of a fusion protein containing the antigenic domain 1 of human cytomegalovirus glycoprotein B and its application in ELISA tests.

The glycoprotein B (gB) of human cytomegalovirus represents a dominant antigen for the humoral immune response. The immunodominant region on gB is the antigenic domain 1 (AD-1), a complex structure that requires a minimal continuous sequence of more than 75 amino acids for antibody binding. In this study, this domain was expressed in Escherichia coli as a fusion protein with beta-galactosidase but yielded insoluble protein aggregates as inclusion bodies. To recover the fusion protein, inclusion bodies were solubilized by two extractions with urea 8 M: and the fusion protein then isolated using gel filtration chromatography. After confirmation of fusion protein antigenicity by Western blotting, the purified product was used as the capturing antigen in an enzyme-linked immunosorbent assay (ELISA) to determine the presence of viral antibodies in serum samples of pregnant women. A cut-off point of approximately 0.2 absorbance units could discriminate the results of seropositive from seronegative pregnant women. The data indicates the potential usefulness of the fusion protein for the development of immunoassay for detection of the HCMV antibodies.

Enzyme-Linked Immunosorbent Assay↗
PubMed2005

Estrogen receptor 2 and progesterone receptor gene polymorphisms and lipid levels in women with different hormonal status.

Sex steroid hormones have multiple effects on lipid metabolism. We investigated the association between two common single nucleotide polymorphisms of the estrogen receptor 2 gene (ESR2), 1082G>A and 1730A>G, and PROGINS polymorphism of the progesterone receptor gene (PGR) with lipoprotein levels in a cross-sectional study with 472 women of European descent. The women were classified into three subgroups according to hormonal status, premenopausal women (n=187; mean age=34+/-9.7 years), postmenopausal women exposed to hormone replacement therapy (HRT) (n=118; 56+/-6.7 years) and postmenopausal women unexposed to HRT (n=167; 58+/-9.8 years). The premenopausal and postmenopausal women exposed to HRT, both carriers of G/A genotype, exhibited LDL-C (P=0.027 and 0.001, respectively) and T-chol levels (P=0.035 and 0.001, respectively) lower than carriers of G/G genotype. This association was not observed in postmenopausal women unexposed to HRT. These results suggest that ESR2 1082G>A genotype may influence LDL-C levels in women with abundant estrogen levels, due to either endogenous or exogenous sources.

Adult↗
PubMed2005

Estrogen-metabolizing gene polymorphisms and lipid levels in women with different hormonal status.

Endogenous and exogenous sex steroid hormones have multiple effects on lipid and lipoprotein metabolism. It is also known that estrogen has antiatherogenic actions, therefore we considered examining whether there was any association between polymorphisms in estrogen-metabolizing genes and lipid levels in women. We investigated the association between variants in genes related to estrogen biosynthesis (CYP19-TTTA(n)) and estrogen catabolism (CYP1A1*2A, CYP1A1*2C, CYP1A2-Asn516Asn, CYP3A4*1B, and COMT-Val158Met) with serum lipid levels in a cross-sectional study with 472 Brazilian women of European descent. They were divided into three subgroups according to their hormonal status: premenopausal women (n=187), postmenopausal women exposed to hormonal replacement therapy (HRT) (n=118), and postmenopausal women unexposed to HRT (n=167). The postmenopausal women receiving HRT who were carriers of the CYP3A4*1B variant showed lower low-density lipoprotein cholesterol levels than wild-type homozygotes. Premenopausal women homozygous for the CYP1A1*2C allele had higher high-density lipoprotein cholesterol levels than heterozygotes. While the CYP1A1*2C variant probably has a higher catalytic activity, the functional implications of the CYP3A4 polymorphism are still uncertain. These data are the first attempt to associate estrogen metabolism genes to lipid levels in women.

Adolescent↗
PubMed2004

Concerted changes in tropical forest structure and dynamics: evidence from 50 South American long-term plots.

Several widespread changes in the ecology of old-growth tropical forests have recently been documented for the late twentieth century, in particular an increase in stem turnover (pan-tropical), and an increase in above-ground biomass (neotropical). Whether these changes are synchronous and whether changes in growth are also occurring is not known. We analysed stand-level changes within 50 long-term monitoring plots from across South America spanning 1971-2002. We show that: (i) basal area (BA: sum of the cross-sectional areas of all trees in a plot) increased significantly over time (by 0.10 +/- 0.04 m2 ha(-1) yr(-1), mean +/- 95% CI); as did both (ii) stand-level BA growth rates (sum of the increments of BA of surviving trees and BA of new trees that recruited into a plot); and (iii) stand-level BA mortality rates (sum of the cross-sectional areas of all trees that died in a plot). Similar patterns were observed on a per-stem basis: (i) stem density (number of stems per hectare; 1 hectare is 10(4) m2) increased significantly over time (0.94 +/- 0.63 stems ha(-1) yr(-1)); as did both (ii) stem recruitment rates; and (iii) stem mortality rates. In relative terms, the pools of BA and stem density increased by 0.38 +/- 0.15% and 0.18 +/- 0.12% yr(-1), respectively. The fluxes into and out of these pools-stand-level BA growth, stand-level BA mortality, stem recruitment and stem mortality rates-increased, in relative terms, by an order of magnitude more. The gain terms (BA growth, stem recruitment) consistently exceeded the loss terms (BA loss, stem mortality) throughout the period, suggesting that whatever process is driving these changes was already acting before the plot network was established. Large long-term increases in stand-level BA growth and simultaneous increases in stand BA and stem density imply a continent-wide increase in resource availability which is increasing net primary productivity and altering forest dynamics. Continent-wide changes in incoming solar radiation, and increases in atmospheric concentrations of CO2 and air temperatures may have increased resource supply over recent decades, thus causing accelerated growth and increased dynamism across the world's largest tract of tropical forest.

Carbon Dioxide↗
PubMed2004

Pattern and process in Amazon tree turnover, 1976-2001.

Previous work has shown that tree turnover, tree biomass and large liana densities have increased in mature tropical forest plots in the late twentieth century. These results point to a concerted shift in forest ecological processes that may already be having significant impacts on terrestrial carbon stocks, fluxes and biodiversity. However, the findings have proved controversial, partly because a rather limited number of permanent plots have been monitored for rather short periods. The aim of this paper is to characterize regional-scale patterns of 'tree turnover' (the rate with which trees die and recruit into a population) by using improved datasets now available for Amazonia that span the past 25 years. Specifically, we assess whether concerted changes in turnover are occurring, and if so whether they are general throughout the Amazon or restricted to one region or environmental zone. In addition, we ask whether they are driven by changes in recruitment, mortality or both. We find that: (i) trees 10 cm or more in diameter recruit and die twice as fast on the richer soils of southern and western Amazonia than on the poorer soils of eastern and central Amazonia; (ii) turnover rates have increased throughout Amazonia over the past two decades; (iii) mortality and recruitment rates have both increased significantly in every region and environmental zone, with the exception of mortality in eastern Amazonia; (iv) recruitment rates have consistently exceeded mortality rates; (v) absolute increases in recruitment and mortality rates are greatest in western Amazonian sites; and (vi) mortality appears to be lagging recruitment at regional scales. These spatial patterns and temporal trends are not caused by obvious artefacts in the data or the analyses. The trends cannot be directly driven by a mortality driver (such as increased drought or fragmentation-related death) because the biomass in these forests has simultaneously increased. Our findings therefore indicate that long-acting and widespread environmental changes are stimulating the growth and productivity of Amazon forests.

Biodiversity↗
PubMed2004

Involvement of the major histocompatibility complex region in the genetic regulation of circulating CD8 T-cell numbers in humans.

Variability in T-lymphocyte numbers is partially explained by a genetic regulation. From studies in animal models, it is known that the Major Histocompatibility Complex (MHC) is involved in this regulation. In humans, this has not been shown yet. The objective of the present study was to test the hypothesis that genes in the MHC region influence the regulation of T-lymphocyte numbers. Two approaches were used. Association studies between T-cell counts (CD4(+) and CD8(+)) or total lymphocyte counts and HLA class I alleles (A and B) or mutations in the HFE (C282Y and H63D), the hemochromatosis gene, in an unrelated population (n = 264). A second approach was a sibpair correlation analysis of the same T-cell counts in relation to HLA-HFE haplotypes in subjects belonging to 48 hemochromatosis families (n = 456 sibpairs). In the normal population, results showed a strong statistically significant association of the HLA-A*01 with high numbers of CD8(+) T cells and a less powerful association with the HLA-A*24 with low numbers of CD8(+) T cells. Sibpair correlations revealed the most significant correlation for CD8(+) T-cell numbers for sibpairs with HLA-HFE-identical haplotypes. This was not observed for CD4(+) T cells. These results show that the MHC region is involved in the genetic regulation of CD8(+) T-cell numbers in humans. Identification of genes responsible for this control may have important biological and clinical implications.

Adolescent↗
PubMed2001

Clinical outcome of Crohn's disease: analysis according to the vienna classification and clinical activity.

The aim of this study was to describe the clinical course of Crohn's disease (CD) in a well-defined, homogeneous groups of patients. A total of 480 patients with CD were followed up from diagnosis up to 20 years. Definitions of patient subgroups were made according to the Vienna Classification. Markov chain analysis was used to estimate the probabilities of remissions and relapses during the disease course. Both age at diagnosis and behavior were associated with different disease locations. Patients with ileal disease had a greater need for surgical and a lesser need for immunosuppressive treatment; patients with ileocolonic disease were diagnosed at an earlier age and showed a lower probability of remaining in remission during the disease course; patients with colonic disease needed less surgical or steroid treatments; patients with intestinal penetrating disease were frequently submitted to abdominal surgery, whereas those with anal-penetrating disease often needed immunosuppressive treatment. Approximately 40% of the patients were in clinical remission at any time, but only about 10% maintained a long-term remission free of steroids after their initial presentation. A more benign clinical course could be predicted in patients who stay in remission in the year after diagnosis. The grouping of patients with CD according to the Vienna Classification and/or the clinical activity in the year after diagnosis is useful in predicting the subsequent course of disease.

Adolescent↗
PubMed2000

The TaqI A1 allele of the dopamine D2 receptor gene and alcoholism in Brazil: association and interaction with stress and harm avoidance on severity prediction.

Allele and genotype frequencies of the TaqI A polymorphism of dopamine D2 receptor (DRD2) gene were compared in 115 alcohol-dependent Brazilian males and 114 ethnically matched controls. Regression analyses were performed to test for an interactive effect between the DRD2 TaqI A1 allele and measures of stress and harm avoidance on severity of alcoholism and number of antisocial personality symptoms. A slightly positive association of DRD2 TaqI A1 genotypes with alcoholism was observed, by standard and molecular heterosis approaches. The DRD2 TaqI A1 allele showed significant interaction with stress and harm avoidance in predicting the severity of physiologic dependence, and with harm avoidance for the number of antisocial personality symptoms. Separate partial correlation analyses showed that stress-related variables were significantly correlated with severity scores in alcoholics with the allele, but not in those without it. This is the first demonstration of an interaction between a genetic polymorphism and stress-related measures on the severity of psychiatric disorders.

Adult↗
PubMed2000

Four novel MSH2 / MLH1 gene mutations in portuguese HNPCC families.

Hereditary non-polyposis colorectal cancer (HNPCC) is considered to be determined by germline mutations in the mismatch repair (MMR) genes, especially MSH2 and MLH1. While screening for mutations in these two genes in HNPCC portuguese families, 3 previously unreported MSH2 and 1 MLH1 mutations have been identified in families meeting strict Amsterdam criteria. Hum Mutat 15:116, 2000.

Adaptor Proteins, Signal Transducing↗
PubMed2000

Eleven novel APC mutations identified in Portuguese FAP families.

Germline mutations of the adenomatous polyposis coli (APC) gene are responsible for familial adenomatous polyposis (FAP), an autosomal dominant predisposition to colorectal cancer. In the present study we screened all of the exons of the APC gene in individuals belonging to 85 Portuguese FAP families. We here report eleven novel mutations which are predominantly frameshifts or single base substitutions, resulting in premature stop codons. Hum Mutat 16:178, 2000.

Adenomatous Polyposis Coli↗
PubMed2000

Search for evidence of a Th2 profile in HIV+ patients.

BACKGROUND: Hypersensitivity dermatoses are common in human immunodeficiency virus-positive (HIV+) patients, particularly as the disease progresses. Studies have shown that a switch to T-helper 2 (Th2) might represent a turning point in HIV. This study investigated whether increases in the number of skin mast cells, immunoglobulin E (IgE) serum levels, and eosinophilia, involved in the Th2 response in allergic disease, might also be present in HIV+ patients. If so, these alterations might explain one of the mechanisms of skin hypersensitivity in these patients. METHODS: Forty-five skin biopsies from the normal skin of the upper arm of HIV+ patients and 15 controls were included in the study. HIV+ individuals were classified into three equal categories according to their immunologic status: Category I (< 200/microL), Category II (200-499/microL), and Category III (> 500/microL). Anti-tryptase antibody was employed in tissue sections to show mast cells; IgE serum levels and eosinophils in peripheral blood count were investigated; delayed-type hypersensitivity (DTH) skin tests (candidin, trichophytin, and PPD 2U) were evaluated. RESULTS: Normal cutaneous mast cell and eosinophil counts were the same in all categories and in the control group, but increased IgE levels (P < 0. 01) and DTH skin test anergy (P < 0.006) were observed among acquired immunodeficiency syndrome (AIDS) patients. CONCLUSIONS: The density of skin mast cells in HIV infection was not modified in the course of the disease. Mast cells do not seem to be primarily responsible for triggering hypersensitivity dermatoses among AIDS patients, although data in support of the Th2 response, as seen in increased IgE serum levels and DTH anergy, are present.

Adult↗
PubMed1999

Isolated trigeminal neuropathy due to trigeminal nerve root hemorrhage.

BACKGROUND: Isolated trigeminal neuropathy is uncommon; causes include trauma, inflammation, or neoplasm. METHODS: We report a patient who fell and struck his head during a myocardial infarction, was treated with streptokinase, and developed symptoms and signs of an isolated trigeminal sensory neuropathy. RESULTS: Imaging showed hemorrhage in the trigeminal nerve root; follow-up imaging showed resolution of the hemorrhage, but no underlying structural lesion. CONCLUSION: A combination of head trauma plus thrombolysis resulted in an isolated trigeminal neuropathy.

Cerebral Hemorrhage↗
PubMed1999

Dopamine D4 receptor gene and personality dimensions in Brazilian male alcoholics.

The presence of the seven-repeat allele of the VNTR in the exon 3 of the dopamine D4 receptor gene (DRD4) has been associated in healthy subjects to the personality trait of novelty seeking. The present study focuses these observations on a sample of Brazilian male alcoholics, evaluated on the temperament dimensions originally described by Cloninger. The genotypes observed are in agreement with those expected under Hardy-Weinberg equilibrium. Subjects with the seven-repeat allele manifest lower harm avoidance scores. No significant differences between subjects with or without the seven-repeat allele in the scores of novelty seeking or reward dependence were observed. The lack of association between novelty seeking and the DRD4 exon 3 polymorphism is further corroborated by the fact that the comorbid antisocial personality disorder is not associated to the presence of the seven-repeat allele. These results could be explained by a biological connection between the personality dimensions of novelty seeking and harm avoidance.

Adult↗
PubMed1995

Epidemic cholera in rural El Salvador: risk factors in a region covered by a cholera prevention campaign.

In response to the Latin American cholera epidemic, El Salvador began a prevention programme in April 1991. The first case was confirmed in August, and 700 cases were reported within 3 months. A matched case-control study was conducted in rural La Libertad Department in November 1991. Illness was associated with eating cold cooked or raw seafood (odds ratio [OR] = 7.0; 95% confidence limits [CL] = 1.4, 35.0) and with drinking water outside the home (OR = 8.8; 95% CL = 1.7, 44.6). Assertion of knowledge about how to prevent cholera (OR = 0.2; 95% CL = 0.1, 0.8) and eating rice (OR = 0.2; 95% CL = 0.1, 0.8) were protective. More controls than patients regularly used soap (OR = 0.3; 95% CL = 0.1, 1.0). This study demonstrated three important points for cholera prevention: (1) seafood should be eaten cooked and hot; (2) populations at risk should be taught to treat household drinking water and to avoid drinking water outside the home unless it is known to be treated; and (3) education about hygiene can be an important tool in preventing cholera.

Adolescent↗